Audi A6 Quatro 3.0 My check engine lights are on, so I use a cheap OBDII scanner and it says P0401 and P0402 error code which means the secondary air injection system has insufficient flow. I tried bring the car to a car mechanic and he couldn't even get his OBD scanner to read the code. Is this an easy fix or do I have to go back to the Audi dealer for service to get this fix?
Very interesting. Added some cleaner to the fuel and after a week, the problem magically disappear. {black}:idontknow:
EVAP control valve solenoid possible but more likely a clogged EGR valve. Either remove and clean or replace with new.
I checked the gas cap and also ensure the seal is good. Could I have a bad or clogged pump somewhere? It looks like the P0401 and P0402 are generic error codes. Many youtube DIY videos offers different solutions because it is different car make and models so it is quickly gets confusing. I couldn't find one exact match video for Audi A6 Quattro 3.0 2012.